(CNN) – Essential American interests are at stake as Syria's two-year-old civil war continues to rage, President Barack Obama asserted in an exclusive interview with CNN that aired Friday.

Speaking with "New Day" anchor Chris Cuomo, Obama defended his administration's decision to not intervene militarily in the conflict so far, but predicted that American focus on the country's strife would be necessary for the fighting to come to an end.
"I think it is fair to say that, as difficult as the problem is, this is something that is going to require America's attention and hopefully the entire international community's attention," Obama said.

His remarks came the same week rebels in Syria alleged Syrian President Bashar al-Assad used chemical weapons in an attack on rebels. The assault killed more than a thousand people, the rebels claimed.

Obama said the United States, along with United Nations inspectors, were gathering information on the attack, but that preliminary signs point to a "big event of grave concern."

"It is very troublesome," he said. "That starts getting to some core national interests that the United States has, both in terms of us making sure that weapons of mass destruction are not proliferating, as well as needing to protect our allies, our bases in the region."

A year ago, Obama laid out his barometer for greater action in Syria during a White House press conference. He said in August 2012 that "a red line for us is we start seeing a whole bunch of chemical weapons moving around or being utilized."

"That would change my calculus," Obama said at the time. "That would change my equation."

Earlier this summer, the Obama administration announced it would provide military support to rebel fighters because al-Assad's forces had used chemical weapons. Some members of Congress have called for greater U.S. involvement.

In the CNN interview, Obama countered those calls by pointing both to international law and to the cost of intervening further in the Syrian conflict. He also noted the billions of U.S. dollars still being spent in Afghanistan as the war in that country winds down.

"Sometimes what we've seen is that folks will call for immediate action, jumping into stuff, that does not turn out well, gets us mired in very difficult situations, can result in us being drawn into very expensive, difficult, costly interventions that actually breed more resentment in the region," he said.